Light guides can be used to provide functional or decorative lighting. Functional lighting refers to lighting that is used for the purpose of illuminating an object or area to make the object or area more conspicuous. Decorative lighting refers to lighting that is used for aesthetic purposes. Often, light guides are used for both functional and decorative purposes.
A light source can be used to illuminate one or more light guides such that light is transmitted through the light guides via total internal reflection (TIR). Light guides may provide side lighting, in which light is emitted from the sides of the guides. In addition, light guides may provide end lighting, in which light is emitted from the end of the guides. A variety of different light extraction techniques using notches or coatings, for example, can be applied to the light guides to cause light to be emitted from the sides of the light guides in a controlled or random manner.
Lighting systems that implement light guides generally have one or more light sources that illuminate the light guide. For example, incandescent light sources, or solid state light sources such as light emitting diodes are often used to illuminate light guides. The light source may reside in a light source assembly, also referred to as an illuminator. The light can be transmitted down the light guide, and may change colors or pulsate over time to provide the desired functional or decorative effect.